FcRn-dependent IgG accumulation in adipose tissue unmasks obesity pathophysiology

Evidence from laboratory and animal studies provides groundwork for understanding mechanisms and potential before human studies continue.

• Level A · Stronger Clinical Evidence
• Level B · Emerging clinical evidence with positive signals
• Level C · Early human research exploring benefits
• Level D · Scientific groundwork from lab and animal studies
• Emerging · Emerging topic under active research

Abstract (original English)

Immunoglobulin G (IgG) is traditionally recognized as a plasma protein that neutralizes antigens for immune defense. However, our research demonstrates that IgG predominantly accumulates in adipose tissue during obesity development, triggering insulin resistance and macrophage infiltration. This accumulation is governed by neonatal Fc receptor (FcRn)-dependent recycling, orchestrated in adipose progenitor cells and macrophages during the early and late stages of diet-induced obesity (DIO), respectively. Targeting FcRn abolished IgG accumulation and rectified insulin resistance and metabolic degeneration in DIO. By integrating artificial intelligence (AI) modeling with in vivo and in vitro experimental models, we unexpectedly uncovered an interaction between IgG's Fc-CH3 domain and the insulin receptor's ectodomain. This interaction hinders insulin binding, consequently obstructing insulin signaling and adipocyte functions. These findings unveil adipose IgG accumulation as a driving force in obesity pathophysiology, providing a novel therapeutic strategy to tackle metabolic dysfunctions.

Evidence level

Evidence from laboratory and animal studies provides groundwork for understanding mechanisms and potential before human studies continue.

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